The short answer

Have a professional check your gas furnace once a year, before the cold sets in, and do a few simple checks yourself each month of winter: change the filter, keep the area around the furnace clear, make sure your carbon monoxide alarms work, and listen for anything new. If you ever smell gas, leave the house and call the gas company from outside. Do not flip switches or look for the source.

Do this yourself before the first cold snap

  • Check the filter. A dirty filter makes the furnace work harder and can cause it to overheat and shut off. Replace it if it looks gray and clogged. Many homes need a new one every one to three months in winter; follow your filter's label.
  • Turn the thermostat to heat and set it a few degrees above room temperature. The furnace should start, the blower should come on, and the house should warm up.
  • Open every supply vent and return grille. Move furniture, rugs and boxes away from them. Blocked airflow is a common cause of uneven heat.
  • Clear the furnace area. Nothing stored against or on top of the furnace, and no paint, cleaners or aerosols nearby. Keep clear space around it for air and service.
  • Look at the exhaust and intake pipes outside on a high-efficiency furnace. Make sure snow, ice, leaves or a nest are not blocking them. A blocked pipe can make the furnace shut down.
  • Listen and smell on the first run. A short burnt-dust smell on the first day of heating is common. Banging, squealing, grinding or a smell that does not fade is not.

Carbon monoxide: the safety check that matters most

A gas furnace that is cracked, dirty or poorly vented can put carbon monoxide into the home. You cannot see or smell it.

  • Put a carbon monoxide alarm on every level and near bedrooms.
  • Press the test button and replace batteries now. Check the date on the alarm and replace it when it expires.
  • If an alarm goes off, get everyone outside and call 911 from outside. Do not stay to find the cause.

What a professional checkup covers

A real annual service goes beyond a glance. A good technician will typically:

  • Inspect the heat exchanger for cracks or corrosion
  • Check the burners, ignition and flame
  • Test the safety controls and limit switches
  • Check the venting and flue for blockage or leaks
  • Check gas connections for leaks
  • Clean or check the blower, and look at the motor and belt where there is one
  • Check the condensate drain on high-efficiency furnaces, which can freeze or clog
  • Measure temperature rise and airflow, and confirm the thermostat is calling for heat correctly

The flame should burn mostly steady and blue. A lazy yellow or orange flame, soot, or a flame that flickers or lifts is a sign something needs service.

Signs to call now

  • Smell of gas (leave the house first, then call)
  • Carbon monoxide alarm sounding
  • The furnace short cycles (turns on and off quickly)
  • Yellow or orange flame, soot or scorch marks around the furnace
  • Water pooling around the furnace
  • Loud banging, squealing or grinding
  • Heat that is uneven, weak, or gone
  • A furnace more than 15 to 20 years old that has started needing repairs

Why it matters in North Idaho

When it is well below freezing, a furnace that quits is not an inconvenience, it is a risk to your pipes and to anyone in the house. Getting it checked in the fall means problems are found when technicians have time, not on the coldest night of the year. If you travel or own a second home, a furnace that fails while you are away can freeze pipes before anyone notices.

What to do next

Book the checkup before the first hard freeze. If you want one point of contact for it, Simply Young coordinates vetted, licensed heating professionals, so you get a clear scope and a single person to call. Request a consultation below.